How depositional environments impact the microwear preservation of quartz artifacts: insights from the Oldowan of the Shungura Formation (Ethiopia)

  1. Aline Galland
  2. Ignacio Clemente-Conte
  3. Jean-Renaud Boisserie
  4. Anne Delagnes

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Abstract

The function of Oldowan tools is a key aspect of early hominin subsistence in eastern Africa. The rarity of the sites, the preservation of the assemblages and raw materials are limiting factors in the functional study of Early Pleistocene assemblages. The archaeological occurrences from Member F of the Shungura Formation (Ethiopia) have a precise chronostratigraphic framework (2.324 ± 0.020 Ma to 2.271 ± 0.041 Ma), a detailed reconstruction of depositional environments, and artifacts produced mainly from small quartz pebbles that are highly resistant to chemical and mechanical alterations. The studied archaeological material comprises artifacts from 12 occurrences and three environmental contexts (floodplain, point bar, and channel lag). As a baseline for distinguishing taphonomic damage from use-wear, and for assessing the preservation of use-wear in the archaeological record, we characterized macroscopic and microscopic surface alterations resulting from fluvial transport and aeolian abrasion experiments. Despite the good preservation of the lithic assemblages at a macroscopic scale, variations were observed at a microscopic level corresponding to the depositional environment. Understanding the link between taphonomic alterations on quartz and the type of deposits leads to better recognition and interpretation of potential use-wear on these ancient artifacts.

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  1. Peer Community in Archaeology

    The preservation of microwear on lithic artifacts is a central concern in the study of early technological behavior. This is particularly true for Early Pleistocene assemblages, where site preservation, raw material properties, and depositional contexts can all affect the visibility and integrity of use-wear traces. In this context, the work by Galland et al. offers a substantial contribution to the methodological approach of functional analysis on quartz artifacts, a raw material both ubiquitous and challenging within Oldowan assemblages in eastern Africa.

    The study by Galland et al. (2025) focuses on a series of archaeological artifacts from Member F of the Shungura Formation (Lower Omo Valley, Ethiopia) distributed across different depositional environments: floodplain, point bar, and channel lag. All assemblages are composed predominantly of small quartz pebbles, and the artifacts show good preservation at the macroscopic level. However, the key issue addressed is how microscopic surface modifications vary depending on the sedimentary context, and how these modifications can be distinguished from use-wear produced during tool use.

    To approach this problem, a comparative experimental protocol specifically designed to characterize the effects of fluvial transport and aeolian abrasion on quartz clasts has been developed and applied. This represents an important methodological step, as previous use-wear studies have often been hampered by the difficulty of disentangling taphonomic damage from intentional use-related traces, especially on highly resistant and light-reflective materials such as quartz.

    The comparative analysis between experimental and archaeological materials highlights how depositional environments differentially affect microscopic surface alterations, even when macroscopic preservation appears relatively uniform. Specific patterns of rounding, micro-scarring, and polish formation linked to sediment dynamics are documented. These findings have direct implications for evaluating the functional potential of the Shungura assemblages and, more broadly, for any interpretation that relies on the integrity of surface traces on quartz artifacts.

    A systematic and transparent recording approach has been adopted throughout the study. Clear definitions of the observed alterations, a structured classification protocol, and a comparative interpretative framework applicable beyond the studied sites are provided. The results stress the need for caution in functional studies on early quartz assemblages and establish a solid baseline for future work aiming to identify genuine use-wear signals under variable taphonomic conditions.

    This manuscript is a valuable contribution to the methodological literature on Early Stone Age lithic analysis. It offers a robust combination of experimental and archaeological evidence, presented with clarity and precision. Its relevance extends beyond the Shungura Formation, offering practical tools for researchers working in similar open-air contexts with comparable raw materials. By anchoring functional interpretations in a detailed understanding of taphonomic processes, this study helps reinforce the empirical foundations of behavioral inference in early prehistory.

    This work will serve as an important methodological reference for archaeologists working on early quartz-based industries and for all researchers concerned with the preservation and recognition of use-wear in ancient lithic contexts.

    References

    Aline Galland, Ignacio Clemente-Conte, Jean-Renaud Boisserie, Anne Delagnes (2025) How depositional environments impact the microwear preservation of quartz artifacts: insights from the Oldowan of the Shungura Formation (Ethiopia). PaleorXiv, ver.3 peer-reviewed and recommended by PCI Archaeology https://doi.org/10.31233/osf.io/9k8p3_v3

  2. Version published to 10.31233/osf.io/9k8p3_v3 on OSF Preprints
  3. Version published to 10.31233/osf.io/9k8p3_v2 on OSF Preprints
  4. Version published to 10.31233/osf.io/9k8p3 on OSF Preprints